Most of us are hard-wired to go to sleep and wake up at certain times of day. Some of us are early-to-bed-and-early-to-risers, while others prefer to stay up late and wake up late. Many of us fall somewhere in between. Researchers refer to this preference for sleep times as our "chronotype."
Chronotype is "largely determined genetically," explains Sunita Sah, one of the authors of the Psychological Science study. "But it can change over time. Teenagers and students might find their chronotype shifts as they get older." But it's quite difficult to deliberately reset your body's sleep clock in a short period of time, as any new parent knows.
Sah and her colleagues found that this internal clock also affects our ability to behave ethically at different times of day. To make a long research paper short, when we're tired we tend to fudge things and cut corners.
Sah measured this by finding out the chronotypes of 140 people via a standard self-assessment questionnaire, and then asking them to complete a task in which they rolled dice to win raffle tickets - higher rolls, more tickets. Participants were randomly assigned to either early morning or late evening sessions. Crucially, the participants self-reported their dice rolls.
You'd expect the dice rolls to average out to around 3.5. So the extent to which a group's average exceeds this number is a measure of their collective result-fudging. "Morning people tended to report higher die-roll numbers in the evening than the morning, but evening people tended to report higher numbers in the morning than the evening," Sah and her co-authors wrote. You can see the differences in the chart below.
These results "cast doubt on the stereotype that evening people are somehow dissolute," the authors conclude - early risers are just as likely to cheat when taken out of their temporal comfort zone.
These findings have pretty big implications for the workplace. For one, they suggest that the one-size-fits-all 9-to-5 schedule is practically an invitation to ethical lapses. "Employers could consider this when creating their own work structures, " Sah says. "They might want to think about flex time, about matching individuals with what's best for them."
For individual workers, the take-home message is "know thy chronotype, know thyself." Schedule your most challenging tasks for the times of day when you know you'll be most alert. Alternatively, if you're feeling Machiavellian, you could put off your difficult tasks until you're tired and exhausted, knowing that you'll fudge your way through them with ease.
"One of the important points the study really reflects is that good people can make unethical decisions," Sah says. "Ethics are not a stable characteristic over time."